Added E1 boss

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

lib/features/entities/enemies/bosses/hans_grosse.dart

@@ -0,0 +1,154 @@
+import 'dart:math' as math;
+
+import 'package:wolf_dart/classes/coordinate_2d.dart';
+import 'package:wolf_dart/features/difficulty/difficulty.dart';
+import 'package:wolf_dart/features/entities/enemies/enemy.dart';
+import 'package:wolf_dart/features/entities/entity.dart';
+import 'package:wolf_dart/features/entities/map_objects.dart';
+
+class HansGrosse extends Enemy {
+  static const double speed = 0.04;
+  static const int _baseSprite = 291;
+  bool _hasFiredThisCycle = false;
+
+  HansGrosse({
+    required super.x,
+    required super.y,
+    required super.angle,
+    required super.mapId,
+    required Difficulty difficulty,
+  }) : super(
+         spriteIndex: _baseSprite,
+         state: EntityState.idle,
+       ) {
+    // Boss health scales heavily with difficulty
+    health = switch (difficulty.level) {
+      0 => 850,
+      1 => 950,
+      2 => 1050,
+      _ => 1200,
+    };
+    damage = 20; // Dual chainguns hit hard!
+  }
+
+  static HansGrosse? trySpawn(
+    int objId,
+    double x,
+    double y,
+    Difficulty difficulty,
+  ) {
+    if (objId == MapObject.bossHansGrosse) {
+      return HansGrosse(
+        x: x,
+        y: y,
+        angle: MapObject.getAngle(objId),
+        mapId: objId,
+        difficulty: difficulty,
+      );
+    }
+    return null;
+  }
+
+  @override
+  void takeDamage(int amount, int currentTime) {
+    if (state == EntityState.dead) return;
+
+    health -= amount;
+    lastActionTime = currentTime;
+
+    if (health <= 0) {
+      state = EntityState.dead;
+      isDying = true;
+    }
+    // Note: Bosses do NOT have a pain state! They never flinch.
+  }
+
+  @override
+  ({Coordinate2D movement, double newAngle}) update({
+    required int elapsedMs,
+    required Coordinate2D playerPosition,
+    required bool Function(int x, int y) isWalkable,
+    required void Function(int damage) onDamagePlayer,
+    required void Function(int x, int y) tryOpenDoor,
+  }) {
+    Coordinate2D movement = const Coordinate2D(0, 0);
+
+    // Bosses lack directional sprites, they always look straight at the player
+    double newAngle = position.angleTo(playerPosition);
+
+    checkWakeUp(
+      elapsedMs: elapsedMs,
+      playerPosition: playerPosition,
+      isWalkable: isWalkable,
+      baseReactionMs: 50,
+    );
+
+    double distance = position.distanceTo(playerPosition);
+
+    switch (state) {
+      case EntityState.idle:
+        spriteIndex = _baseSprite;
+        break;
+
+      case EntityState.patrolling:
+        if (distance > 1.5) {
+          double moveX = math.cos(newAngle) * speed;
+          double moveY = math.sin(newAngle) * speed;
+          movement = getValidMovement(
+            Coordinate2D(moveX, moveY),
+            isWalkable,
+            tryOpenDoor,
+          );
+        }
+
+        int walkFrame = (elapsedMs ~/ 150) % 4;
+        spriteIndex = (_baseSprite + 1) + walkFrame;
+
+        if (distance < 8.0 && elapsedMs - lastActionTime > 1000) {
+          if (hasLineOfSight(playerPosition, isWalkable)) {
+            state = EntityState.attacking;
+            lastActionTime = elapsedMs;
+            _hasFiredThisCycle = false;
+          }
+        }
+        break;
+
+      case EntityState.attacking:
+        int timeShooting = elapsedMs - lastActionTime;
+        if (timeShooting < 150) {
+          spriteIndex = _baseSprite + 5; // Aiming
+        } else if (timeShooting < 300) {
+          spriteIndex = _baseSprite + 6; // Firing
+          if (!_hasFiredThisCycle) {
+            onDamagePlayer(damage);
+            _hasFiredThisCycle = true;
+          }
+        } else if (timeShooting < 450) {
+          spriteIndex = _baseSprite + 7; // Recoil
+        } else {
+          state = EntityState.patrolling;
+          lastActionTime = elapsedMs;
+        }
+        break;
+
+      case EntityState.dead:
+        if (isDying) {
+          int deathFrame = (elapsedMs - lastActionTime) ~/ 150;
+          if (deathFrame < 4) {
+            spriteIndex = (_baseSprite + 8) + deathFrame;
+          } else {
+            spriteIndex = _baseSprite + 11; // Final dead frame
+            isDying = false;
+          }
+        } else {
+          spriteIndex = _baseSprite + 11;
+        }
+        break;
+
+      default:
+        break;
+    }
+
+    return (movement: movement, newAngle: newAngle);
+  }
+}

lib/features/entities/entity_registry.dart

@@ -1,6 +1,7 @@
 import 'package:wolf_dart/features/difficulty/difficulty.dart';
 import 'package:wolf_dart/features/entities/collectible.dart';
 import 'package:wolf_dart/features/entities/decorative.dart';
+import 'package:wolf_dart/features/entities/enemies/bosses/hans_grosse.dart';
 import 'package:wolf_dart/features/entities/enemies/dog.dart';
 import 'package:wolf_dart/features/entities/enemies/guard.dart';
 import 'package:wolf_dart/features/entities/enemies/mutant.dart';
@@ -26,6 +27,9 @@ abstract class EntityRegistry {
     Mutant.trySpawn,
     Dog.trySpawn,
 
+    // Bosses
+    HansGrosse.trySpawn,
+
     // Everything else
     Collectible.trySpawn,
     Decorative.trySpawn,